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Biomedical subjects

R G Feldman

Publications and source records attributed to R G Feldman.

At least 91 records · Page 5Linked to original sources
PubMed1985

Long-term follow-up after single toxic exposure to trichloroethylene.

In an earlier report [Feldman and Lessell, 1967], neurologic findings following acute intoxication to trichloroethylene were presented. Facial anesthesia, asymmetric pupillary responses, and electrical evidence of sensorimotor neuropathy accompanied neuropsychological deficits, manifested by difficulty in solving sequential problems and poor memory affecting the acquisition of new information. Twelve years after the initial exposure, patches of hypalgesia over the malar eminences persisted and corneal reflexes remained absent, although sensation in the snout region was totally normal. Neuropsychological test results continued to demonstrate impaired attention and short-term memory as well as diminished visuospatial organization and sequencing, 16 years after exposure. In addition, MMPI profile and interview suggested continued depressive symptomatology. Eighteen years after exposure, findings included paresthesia and hypalgesia in the malar area of the face as well as myokymia of the facial muscles. Facial nerve latency studies were normal as were pattern shift visual evoked responses. The patient continued to have large pupils that reacted asymmetrically to light. In the right eye, contraction was synchronous in all segments of the sphincter. In the left eye, there was segmental contraction, suggestive of a tonic pupil. This report offers evidence of long-term residual oculomotor and ciliary reflex dysfunction as well as impaired neuropsychological performance as a result of acute TCE intoxication.

Affective Symptoms↗
PubMed1985

Occupational lead neurotoxicity: improvement in behavioural effects after reduction of exposure.

To evaluate critical exposure levels and the reversibility of lead neurotoxicity a group of lead exposed foundry workers and an unexposed reference population were followed up for three years. During this period, tests designed to monitor neurobehavioural function and lead dose were administered. Evaluations of 160 workers during the first year showed dose dependent decrements in mood, visual/motor performance, memory, and verbal concept formation. Subsequently, an improvement in the hygienic conditions at the plant resulted in striking reductions in blood lead concentrations over the following two years. Attendant improvement in indices of tension (20% reduction), anger (18%), depression (26%), fatigue (27%), and confusion (13%) was observed. Performance on neurobehavioural testing generally correlated best with integrated dose estimates derived from blood lead concentrations measured periodically over the study period; zinc protoporphyrin levels were less well correlated with function. This investigation confirms the importance of compliance with workplace standards designed to lower exposures to ensure that individual blood lead concentrations remain below 50 micrograms/dl.

Behavior↗
PubMed1985

[Alzheimer's presenile dementia transmitted in an extended kindred].

Forty-three patients affected with Alzheimer's disease were identified in a kindred of Italian origin, emigrated in part to the U.S.A. and France. Thirteen were known by history, 21 by medical record, and 9 by personal examination, of whom 5 were confirmed histopathologically. The clinical picture was fairly uniform: the first symptom was memory loss beginning around age 40. Psychotic-like symptoms often followed, with rapid evolution into profound dementia, and death around age 50. Akinesia was prominent at a late stage, often with myoclonus. Grand mal seizures sometimes occurred, with occasional interictal spike and wave discharge; repetitive paroxystic periodic discharges were never recorded. A genealogical study, as far as possible free from line bias, has been conducted mainly by analysis of municipal records. 1 435 subjects in 10 generations, linked to affected subjects through ascent/descent or marriage, were listed in a computer file; the corresponding genealogical tree or selected part thereof are generated by computer. Application of Bayesian techniques to demographic data makes possible an estimation of disease probability in subjects for which no clinical data were available: such an estimate was confirmed by the later discovery of a living patient in descent of a subject with 0.7 estimated disease probability. No patient was found in descent from an inbred union known as such. Patients are the only transmitters. The sex ratio is not significantly different from 1. There is no detectable maternal effect. The segregation ratio, as calculated from extensively known sibships, lies in the range 0.65 to 0.89; the lower value itself is significatively higher than the 0.5 value expected in an autosomal dominant monogenic Mendelian transmission. An environment factor is ruled out by the diversity of locations and circumstances in kindred members. Such a kindred may represent an useful model for fundamental studies in Alzheimer's disease and senile dementia of the Alzheimer type.

Adolescent↗
PubMed1984

Transverse myelitis due to meningovascular syphilis.

With the widespread use of serum VDRL testing and penicillin therapy, the prominence of syphilis as an occult cause of neurologic disease has receded. Recent statistics from the Centers for Disease Control, Atlanta, reflect an increase in cases of primary syphilis, promising that more cases of neurosyphilis will arise to confound the unwary clincian. We studied an unusual case of neurosyphilis and developed a rational basis for antibiotic treatment of this condition.

Female↗
PubMed1984

Retrograde amnesia in Parkinson's disease.

Retrograde amnesia was assessed in demented and non-demented Parkinson's patients using a test of remote memory spanning the years from 1920-1979. Results indicated that the demented patients 1) scored significantly below normal controls and 2) had equal impairment for all time periods. This pattern was like that seen in other dementing illnesses (i.e., Huntington's and Alzheimer's diseases), but different from that in amnesic disorders, such as Korsakoff's syndrome. The data, therefore, suggest qualitative differences in pattern of remote memory loss between the dementias and amnesic syndromes.

Aged↗
PubMed1984

Occupational lead neurotoxicity: a behavioural and electrophysiological evaluation. Study design and year one results.

To evaluate the effects of chronic lead exposure on the nervous system in adults, a set of neurobehavioural and electrophysiological tests was administered to 99 lead exposed foundry employees and 61 unexposed workers. Current and past blood lead concentrations were used to estimate the degree of lead absorption; all previous blood lead concentrations had been less than or equal to 90 micrograms/100 ml. Characteristic signs (such as wrist extensor weakness) or symptoms (such as colic) of lead poisoning were not seen. Sensory conduction in the sural nerve was not affected. By contrast, various neurobehavioural functions deteriorated with increasing lead burden. Workers with blood lead concentrations between 40 and 60 micrograms/100 ml showed impaired performance on tests of verbal concept formation, visual/motor performance, memory, and mood. Thus impairment in central nervous system function in lead exposed adults occurred in the absence of peripheral nervous system derangement and increased in severity with increasing lead dose.

Adolescent↗
PubMed1983

The role of occupational lead exposure in the genesis of psychiatric and behavioral disturbances.

In a prospective study of lead neurotoxicity, exposed foundry workers and referents were evaluated using a comprehensive set of neurobehavioral tests. Other performance indexes were used including a questionnaire, physical examination, and nerve conduction testing. Results show increased rates of depression, confusion, anger, fatigue and tension among workers with blood levels over 40 mcg/dl. Other aspects of neurobehavioral function, including verbal concept formation, memory, and visual/motor performance were also impaired. In view of the large number of individuals exposed to lead in their work, specific inquiries should be made of individuals with affectual complaints to clarify the nature of their work and workplace exposure to lead.

Adolescent↗
PubMed1983

Methsuximide for complex partial seizures: efficacy, toxicity, clinical pharmacology, and drug interactions.

Methsuximide (MSM; Celontin) was administered for 8 weeks to 26 patients with complex partial seizures (CPS) refractory to phenytoin and carbamazepine and phenobarbital or primidone. A 50% or greater reduction in CPS frequency was obtained in eight patients. MSM therapy was continued chronically in these eight patients, and five continued to have a 50% or greater reduction in CPS frequency after 3 to 34 months of follow-up. Drowsiness, gastrointestinal disturbance, hiccups, irritability, and headache were the common side effects of MSM. No serious toxicity occurred. N-desmethylmethsuximide was the principal substance detected in plasma and had the following pharmacokinetic values: accumulation half-life, 49.7 hours; time to steady state, 10.4 days; elimination half-life, 72.2 hours; therapeutic range of plasma concentration, 10 to 30 mg per liter. Plasma concentrations of phenytoin and phenobarbital derived from primidone rose significantly (p less than 0.05) after addition of MSM.

Adult↗
PubMed1983

Monitoring neurotoxins in industry: development of a neurobehavioral test battery.

To facilitate the early detection of neurotoxicity in workers exposed to hazardous substances, we assembled a set of noninvasive neurobehavioral tests designed to assess memory, verbal concept formation, visuomotor performance, and mood. The tests were administered to an unexposed reference population and multivariate prediction equations were developed to control for effects of age, gender, and education. To define the briefest test set with appropriate sensitivity and specificity, we applied factor analysis and stepwise logistic regression to data from our referents and a group of lead-exposed workers. As a result, we have identified a comprehensive set of tests that can be administered in less than 40 minutes by trained medical technicians on plant premises and used to detect the early effects of neurotoxic substances on exposed workers. Guidelines for applying this technique to common work-place exposures, including other metals and organic solvents, are discussed.

Emotions↗
PubMed1982

Paraoccupational exposure to mixed solvents.

Exposure to solvent vapors resulted in a sensory neuropathy and mild encephalopathy in a 44-yr-old female cook. The route of exposure was unusual: a ventilation system cross-connection between her restaurant and an adjacent upholstery shop. Possible "paraoccupational" exposures should be sought in cases of neurologic or other unexplained symptoms possibly caused by toxic substances. The role of solvent mixtures in the genesis of nervous system disorders is reviewed.

Adult↗
PubMed1982

Central and peripheral nervous system effects of metals: a survey.

There are several categories of neurologic dysfunction which have been associated with metal intoxication. Many examples of case histories or animal studies where toxicity by metals has produced clinical manifestations and pathophysiologic changes similar to those found in certain primary neurological disorders have been reported. It is easy to make a diagnosis of metal intoxication in a subject whose work history and circumstances of exposure to specific substances is known. Observation of defined safety standards and time weighted averages for a work day in conjunction with environmental monitoring procedures are intended to reduce risk of undue absorption of known potential intoxicants. However, when a patient is seen by a physician and a probable neurological diagnosis is to be made in the absence of a detailed life-work history, the possible relationship to previous or current intoxication may be overlooked. This communication will review several neurological syndromes which have been found in association with metal accumulation.

Behavior↗
PubMed1981

Follow-up studies of workers with bladder neuropathy caused by exposure to dimethylaminopropionitrile.

Following a 1978 outbreak of bladder neuropathy among workers exposed to dimethyl-aminopropionitrile (DMAPN), follow-up studies were performed 2 a after the original epidemic to evaluate the persistence of symptoms among a small group of initially affected workers. Although the overall prevalence of urologic and neurological symptoms fell for the 11 persons interviewed, significantly high rates of persistent symptoms were seen. Of particular concern was the increase in the prevalence of symptoms of sexual dysfunction. Physical examination identified one individual with sensorimotor neuropathy which was initially detected 2 a earlier. Three individuals who had similar neuropathic findings in 1978 were normal 2 a later. Objective neurophysiological and urologic testing revealed evidence of persistent abnormalities in several workers, but most of the objective findings had improved over the 2-a period. The follow-up of residual effects of occupational exposure to neurotoxic substances is essential to the understanding of the course of occupational illnesses.

Adult↗